As a continuation of present investigations of hemorrhagic and septic shock, the kinetics of water and electrolyte distribution are being reevaluated in light of newer concepts of physical chemical states of cell water and ions, as influenced by pH add osmolality. Osmotically active fractions of cell water are to be measured as functions of pH and hypoxia as well as osmolal and electrolyte influences. Body water and its compartments, including blood volume, will be measured by perturbation of these compartments and final volumes of dilution of isotopic and other tracers are being calculated, using curve-fitting programs and our digital computer. The comparative effects of crystalloid and autologous protein-containing replacement solutions on production of pulmonary edema will be measured following controlled hemorrhage. Computer programs are being developed, in association with some of these newer experimental methods, to evaluate more specifically the nature of cellular and extracellular fluid-electrolyte distortions in shock and, ultimately, to define treatment.